Modular femoral components for knee arthroplasty

ABSTRACT

A femoral knee prosthesis system for resurfacing a resected articular surface at the distal end of a femur includes a femoral component adapted to mate with the resected articular surface; and an attachment member. The interior surface of the femoral component is configured to connect to the first attachment member when the femoral component is mated on the resected articular surface of the femur and when the first attachment member is passed through the medial side or the lateral side of the resected articular surface. The femoral component is available in one-piece and two-piece systems. Mating femoral components (e.g., tapered or with lips that interlock with grooves) are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This nonprovisional patent application is a continuation of U.S. patentapplication Ser. No. 10/444,927, filed May 23, 2003, entitled MODULARFEMORAL COMPONENTS FOR KNEE ARTHROPLASTY, which claims the benefit under35 U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No.60/383,348, filed on May 24, 2002, entitled MODULAR FEMORAL COMPONENTSFOR TOTAL KNEE ARTHROPLASTY, the entire disclosures of which are herebyexpressly incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. The Field of the Invention

The present invention relates to femoral components for use in totalknee arthroplasty.

2. Background Technology

During a typical knee arthroplasty procedure, the femur is resected withsurgical instruments in order to form a resected femoral portion, alsoknown as a resected femur. A femoral component typically in the form ofa metal cap is then placed onto the resected femur. The femoralcomponent is typically designed to interact with and articulate againsta tibial component that is mounted onto the resected tibia.

During the arthroplasty procedure, the femoral component is insertedthrough an incision onto the resected femur. The larger and bulkier thefemoral component is, the larger the incision is required to be, thusincreasing the recovery time of the patient, thus increasing the painassociated with the surgery and the recovery time.

Depicted in FIGS. 1 and 2 is one embodiment of a prosthetic femoralcomponent 10 having an interior surface 12 and an exterior surface 14.Interior surface 12 is comprised of a plurality of intersectingsubstantially flat surfaces that correspond to discrete cut surfaces ona femur. Pegs 16 a-b project from interior surface 12 for engaging withthe femur. Pegs 16 a-b are designed to be implanted within the resectedfemur, thereby anchoring the femoral component to the femur. Theexterior surface 14 articulates against the tibial component.

However, the pegs are affixed using a compression fit into the resectedfemur and project from the interior surface, thereby adding to thebulkiness and size of the femoral component, thereby requiring a largerincision during surgery.

What is therefore needed is a femoral component for use in a kneearthroplasty procedure that is not bulky and does not require a largeincision during surgery. What is also needed is a femoral component thatis firmly affixed to the resected femur and is convenient to mountthereon.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention will now be discussed withreference to the appended drawings. It is appreciated that thesedrawings depict only typical embodiments of the invention and aretherefore not to be considered limiting of its scope.

FIG. 1 is a front perspective view of a prior art femoral component;

FIG. 2 is a back perspective view of the prior art femoral componentshown in FIG. 1;

FIG. 3 is a back perspective view of a femoral component of the presentinvention featuring at least one threaded bore formed on the interiorsurface thereof that is configured to receive an attachment memberextended through the resected femur; an optional second threaded boreand attachment member are shown in phantom lines; the attachment membermay be extended through the medial and/or lateral side;

FIG. 4 is a back perspective view of another femoral component of thepresent invention featuring at least one engaging, receiving pocketfilled with a receiving, engaging material that receives and engages atleast one attachment member extended through the resected femur; anoptional additional receiving surface and attachment member(s) are shownin phantom lines;

FIG. 5 is a perspective view of the femoral component of FIG. 3 beingmounted on a resected femur; a receiving surface 66 for an optionalplate 29 of the femoral component is shown in phantom lines;

FIG. 6 is a perspective view of the femoral component of FIGS. 3 and 5shown as being mounted on the resected femur of FIG. 5 and having anattachment member (shown primarily in phantom lines) extended throughthe resected femur and into the femoral component, thereby securing thefemoral component to the femur;

FIG. 7 is a side cross sectional view of an alternative embodiment of afemoral component having inwardly projecting lips shown as being mountedwithin corresponding grooves cut into a resected femur, thereby securingthe femoral component to the resected femur;

FIG. 8 is a perspective view of a femoral component having a taperedinterior surface that is being mounted onto a resected femur having acomplimentary, tapered, mating surface, thereby securing the femoralcomponent to the resected femur;

FIG. 8 a is a cross sectional view of an alternative femoral component,having a non-chamfered, curved surface, shown as mounted onto a resectedfemur, demonstrating that a femoral component having inwardly projectinglips can have a variety of different interior surfaces.

FIG. 9 is a perspective view of an alternative embodiment of a two-piecefemoral component divided lateral to medial;

FIG. 10 is a perspective view of the femoral component shown in FIG. 9in an assembled state;

FIG. 11 is a perspective view of a two-piece femoral component havingmeshing teeth and divided lateral to medial;

FIG. 12 is a perspective view of a two-piece femoral component dividedanterior to posterior;

FIG. 13 is a perspective view of the femoral component shown in FIG. 12in an assembled state;

FIG. 14 is a perspective view of a femoral component divided anterior toposterior and having meshing teeth;

FIGS. 15A-16B demonstrate assembled and exploded views of anothertwo-piece femoral component of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 3-6 depict examples of femoral knee prosthesis systems used inknee arthroplasty wherein the femoral components are readily slid infrom the medial or lateral side through an incision and onto a femoralresection 60 (FIG. 5). An attachment member, such as a bolt or screw canthen be inserted through the femur until contacting the femoralcomponent. The procedure is minimally invasive and does not require aslarge an incision as components having the pegs 16 a-b of FIG. 2. Thebolt, screw or other attachment member securely affixes the femoralcomponent to the resected femur, rather than merely relying upon acompression fit.

FIGS. 7-8A depict examples of femoral components 70, 80 used in kneearthroplasty wherein a mating relationship, e.g., mating lips 78 a-b andgrooves 79 a-b (FIG. 7) or mating tapering surfaces (FIG. 8) maintainthe femoral component on the resected femur.

FIGS. 9-14 depict connectible two-piece end use femoral components 102,131, 161, and 191 used in knee arthroplasty wherein the two parts arereadily, independently slid in from the medial or lateral side throughan incision and then connected and mounted onto a femoral resection.Optionally, one part may be mounted on the femoral resection followed byanother part being connected thereto. Both parts may also be firstmounted, then connected together. An attachment member, such as a boltor screw can then be inserted through the femur until contacting thefemoral component. Optionally, bone cement can be employed to cement thefemoral component to the resected femur.

A coupling member, e.g., a bolt or a screw attaches one part of thefemoral component to another. The procedure is minimally invasive anddoes not require as large an incision as one piece components becauseone part of the femoral component may be placed through the incision,followed the other part of the femoral component. The individual piecesof the femoral component themselves may also be employed without thecorresponding mating piece, such as when only a portion (e.g., a tibialportion) of the component is needed for a particular procedure.

FIGS. 15A-16B depict a connectible two-piece end use femoral component210 used in knee arthroplasty wherein the two parts are readily,independently slid in from the medial or lateral side through anincision and then connected and mounted onto a femoral resection.Optionally, one part may be mounted on the femoral resection followed byanother part being connected thereto. Integral protrusions extendingfrom one part attach the one part of the femoral component to the other.The procedure is minimally invasive and does not require as large anincision as one piece components because one part of the femoralcomponent may be placed through the incision, followed the other part ofthe femoral component. Pegs are employed for anchoring the component ona femoral resection.

Each of these femoral components will now be discussed in greater detailbeginning with reference to FIGS. 3, 5 and 6. FIG. 3 is a backperspective view of a femoral knee prosthesis system 20 for resurfacinga resected articular surface 64 (FIG. 5) at the distal end 62 of a femur60. As shown in FIG. 5, the resected articular surface 64 of the distalend 62 of the femur 60 has a medial side 61 and an opposing lateral side63.

Prosthesis system 20 of FIG. 3 comprises: (i) a U-shaped femoralcomponent 22 having (i) an interior surface 26 adapted to mate with theresected articular surface 64 and (ii) an opposing articulating surface24; (ii) a first attachment member, e.g., elongated bolt 36 having athreaded end; and (iii) a threaded bore 32 formed on interior surface 26of femoral component 22. Bolt 36 is shown having an elongated shaft 250extending between a first end 252 and an opposing second end 254.Threads 256 are formed at first end 252 while an enlarged head 258 ispositioned at second end 254.

Threaded bore 32 is blind and is an example of means formed on theinterior surface 26 of the femoral component 22 for connecting the firstattachment member 36 to the femoral component 22 when the femoralcomponent 22 is mated on the resected articular surface 64 of the femur60 and when the first attachment member 36 is passed through the medialside or the lateral side of the resected articular surface 64.

Threaded bore 32 is angled such that when femoral component 22 is matedon the resected articular surface of femur 60, bolt 36 can be passedthrough medial side 61 or lateral side 63 of the resected articularsurface 64 so as to threadedly engage with the threaded bore 32 (seeFIGS. 5-6).

Femoral component 22 comprises a substantially U-shaped medial condyle28 connected to a substantially U-shaped lateral condyle 30. Femoralcomponent has an anterior end 35 and a posterior end 37. The medialcondyle 28 is connected to the lateral condyle 30 such that an elongatedslot 39 is formed between the lateral condyle and the medial condyle.However, in another embodiment, the femoral component of the presentinvention comprises merely a substantially U-shaped lateral condyle or asubstantially U-shaped medial condyle, depending upon the desiredprocedure.

An optional plate 29 of the femoral component 22 may be employed toprovide differential surface area for engagement with a complementarysurface on the prosthesis.

As further shown in FIG. 3, system 20 comprises (i) an optional secondattachment member 38; and (ii) means (e.g., second threaded bore 34)formed on the interior surface 26 of the femoral component 22 forconnecting the second attachment member 38 to the femoral component 22when the femoral component 22 is mated on the resected articular surface64 of the femur 60 and when the second attachment member 38 is passedthrough the medial side or the lateral side of the resected articularsurface 64.

Optionally, another attachment member may extend into the medial,anterior surface into another threaded bore adjacent bore 32, ifdesired.

Screws, bolts, pins or other forms of fasteners that can be driventhrough femur 60 so as to engage with interior surface 26 of femoralcomponent 22 are each examples of attachment members of the presentinvention. One or more attachment members 36, 38 may attach torespective one or more bores 32, 34. In one embodiment, the attachmentmembers are on opposing sides of the femoral component from each other,as shown in FIG. 3. As mentioned, in another embodiment, the attachmentmembers mount into the same side of the femoral component (see also FIG.4). These attachment members can engage with interior surface 26 byhaving threaded bores (FIG. 3) or by positioning receiving, engagingmaterial on interior surface 42 to which the fasteners can penetrate andengage with, as will now be discussed with reference to FIG. 4.

FIG. 4 is a back perspective view of another femoral knee prosthesissystem 40 comprising (i) a femoral component 41 comprising an interiorsurface 42 adapted to mate with the resected articular surface 64 and anopposing articulating surface 43; (ii) a first attachment member, e.g.,elongated screw 52 having a threaded end 260 and an enlarged head 262;and (iii) a pocket 48 formed on interior surface 42 of femoral component41.

Femoral component 41 has at least one pocket 48 (filled with anengaging, receiving material 49) that receives at least one attachmentmember 52 extended through the resected femur 60; an optional additionalpocket 50 and an additional corresponding attachment member 54 are shownin phantom lines. Pockets 48, 50 filled with such material areadditional examples of means formed on the interior surface 42 of thefemoral component 41 for connecting an attachment member to the femoralcomponent.

Pockets 48, 50 are formed on the interior surface 42 of the femoralcomponent 41 and are filled with an engaging, receiving material, suchas an adhesive (e.g., polymethylmethacrylate) or another material thatis soft enough to receive the attachment member, but can also retain theattachment member therein. Other examples of such a receiving, engagingmaterial include pliable polymers such as Delrin or polyetheretherketonethat are capable of receiving and deforming to the shape of the firstattachment member.

In one embodiment, in addition to the use of a bolt or screw to attachthe femoral component to the prosthesis, a bone cement can be employedto further enhance the adhesion of the femoral component to the resectedfemur. The bone cement can be applied before and/or during mounting ofthe femoral component. For example, the femoral component can bepartially attached and then a syringe or other form of delivery tubeused to inject bone cement between the femoral component and the femur.In addition, a porous or fibrous material such as a wire mesh may beattached to the interior surface 26 of the femoral component 22 tothereby foster bone growth between the femoral component 22 and theresected femur 60 and to provide surface area for attaching the bonecement between the femoral component and the resected femur.

FIG. 5 is a perspective view of the femoral component 22 of FIG. 3 beingmounted on a resected femur 60. A complimentary receiving surface 66 forthe optional plate 29 of the femoral component is shown in phantomlines.

FIG. 6 is a perspective view of the femoral component 22 of FIGS. 3 and5 shown as being mounted on the resected femur 60 of FIG. 5 and havingan attachment member 36 (shown primarily in phantom lines) extendedthrough the resected femur 60 and into the femoral component 22, therebysecuring the femoral component 22 to the femur 60. This attachmenttightly pulls the femoral component 22 toward and onto the femur 60.

FIGS. 5 and 6 also illustrate a method for resurfacing a femur as partof a surgical procedure, comprising (i) resecting an articulatingsurface 64 at a distal end 62 of a femur 60 so as to form a resectedarticular surface 64 extending between a medial side 61 and a lateralside 63; (ii) mounting a femoral component 22 having an interior surface26 on at least a portion of the resected articular surface 64; (iii)passing a first attachment member 36 through the lateral side or themedial side of the resected articular surface 64; and (iv) connectingthe first attachment member 36 to the femoral component 22 so that thefirst attachment member 36 secures the femoral component 22 to theresected articular surface 64.

In one embodiment, the act of resecting an articulating surfacecomprises resecting a medial condyle and a lateral condyle at the distalend of the femur. In FIG. 5, the medial and lateral condyles of femur 60have been resected. As discussed above, femoral component 22 comprises asubstantially U-shaped lateral condyle connected to a substantiallyU-shaped medial condyle.

In another embodiment, the act of resecting an articulating surface 64comprises resecting only a medial condyle or only a lateral condyle atthe distal end 62 of the femur 60, without the other of the medialcondyle or lateral condyle being resected. In such an alternateembodiment, the act of mounting a femoral component on at least aportion of the resected articular surface 64 comprises the femoralcomponent being a unicondular lateral condyle or medial condyle.

In one embodiment, the act of passing a first attachment member 36through the lateral side or the medial side of the resected articularsurface 64 comprises: (i) boring a hole through the femur; and (ii)advancing the first attachment member 36 through the hole. The hole canbe bored through the femur at an oblique angle α, as reflected in FIGS.3 and 6. The hole can be bored by making an incision in the skinadjacent to the femur, properly orienting a tubular alignment guide,then boring the hole with a drill through the alignment guide.Optionally, however, the first attachment member is advanced through thefemur at such an angle α (e.g., by being advanced through a tubularalignment guide used to orient the first attachment member) withoutinitially boring a hole therethrough. In one embodiment the angle α isin the range of approximately 15 to approximately 45 degrees, e.g.,about 30 degrees, but may be a variety of different angles which achievethe result of affixing the femoral component to the femur.

The method of resurfacing the femur may further comprise (i) passing asecond attachment member 38 (FIG. 3) through the lateral side or themedial side of the resected articular surface; and (ii) connecting thesecond attachment member 38 to the femoral component 22 so that thesecond attachment member 38 secures the femoral component 22 to theresected articular surface.

As discussed above, FIGS. 7-8A depict examples of femoral components 70,80 wherein a mating relationship between the femoral component and theresected femur maintains the femoral component on the resected femur.The prosthetic femoral component can come in a variety of alternativeconfigurations.

FIG. 7 is a side cross sectional view of femoral component 70, whichcomprises a “U” shaped main body 71 having an interior surface 73 anexterior surface 75, an anterior end 77 a, and a posterior end 77 b, andanterior and posterior inwardly projecting lips 78 a, 78 b,respectively, extending from an interior surface 73 of the main body 71.As shown, lips 78 a-b are mounted within corresponding grooves 79 a, 79b cut into a resected femur 74, thereby securing the femoral component70 to the resected portion 72 of the femur 74. In one embodiment, mainbody 71 has the same or substantially the same configuration as thefemoral component 22 shown in FIGS. 3, 5 and 6, but has lips 78 a-bprojecting inwardly from the interior surface 73 of respective posteriorand anterior ends 77 a-b thereof. Groove 79 a is formed in an anteriorsurface 72 a of the femur, while groove 79 b is formed in a posteriorsurface 72 b of the femur.

The lips 78 a-b may project inwardly from one or more condyles. Forexample, one posterior lip 78 b may extend from a medial condyle whileanother posterior lip 78 b extends from a lateral condyle. Optionally,posterior lips 78 b may extend from the lateral and the medial condyle.FIG. 7 is representative of a posterior lip 78 b extending from theinterior surface of the lateral and/or medial condyle.

Similarly, the anterior lip 78 a may extend from the interior surface 73of the anterior end 77 a of the lateral or medial condyle, or may extendas a single lip from the interior surface of both the anterior end ofthe medial condyle and the anterior end of the lateral condyle.

Thus, in one embodiment, femoral component 70 comprises (i) a lateralcondyle (e.g., similar to condyle 30 of FIG. 3) having a substantiallyU-shaped configuration and having an interior surface 73 and an opposingexterior surface 75, each extending between an anterior end 77 a and anopposing posterior end 77 b; and (ii) a medial condyle (e.g., similar tocondyle 28 of FIG. 3) having a substantially U-shaped configuration andhaving an interior surface 73 and an opposing exterior surface 75 eachextending between an anterior end 77 a and an opposing posterior end 77b, the medial condyle being connected to the lateral condyle such thatan elongated slot is formed between the lateral condyle and the medialcondyle.

A first engagement lip 78 a projects from the interior surface 73 of atleast the lateral condyle or the medial condyle at the anterior end 77 athereof; and a second engagement lip 78 b projects from the interiorsurface of at least the lateral condyle or medial condyle at theposterior end 77 b thereof.

Mating lips 78 a-b and grooves are an example of a mating relationshipbetween the femoral component 70 and the resected femur 74 thatmaintains the femoral component 70 on the resected femur 74. Otherexamples of such a mating relationship include an embodiment in which asingle mating lip extends from a U-shaped main body into a single grooveon a resected femur.

Thus, femoral component 70 comprises a main body 71 having an interiorsurface 73 and an opposing articulating surface 75 each extendingbetween a lateral side and a medial side, the interior surface 73 havinga substantially U-shaped transverse cross section; and at least one andpreferably first and second lips 78 a-b projecting inwardly from theanterior or posterior end of the interior surface 73 of the body 71.

Cuts are formed on resected femoral surface 72 complementary to interiorsurface 73 with respective complimentary mating grooves 79 a-b beingformed to receive respective lips 78 a-b. In this configuration, femoralcomponent 70 can be laterally slid onto femur 74 so that lips 78 a-b arereceived within the corresponding grooves 79 a-b on femur 74, therebysecuring femoral component 70 to femur 74.

Another method for resurfacing a femur thus comprises: (i) resecting anarticulating surface at a distal end of a femur 74 so as to form aresected articular surface 72 having an anterior surface and a posteriorsurface each extending between a lateral side and a medial side, atleast one of the anterior surface and posterior surface having a groove79 a-b therein; and (ii) sliding a femoral component 70 onto theresected articular surface 72, a lip 78 a-b of the femoral component 70mating with the groove 79 a-b, the femoral component 70 being slidmedial to lateral or lateral to medial.

As shown in FIG. 7, the step of resecting an articulating surfacepreferably comprises forming first and second opposing grooves 79 a-b inthe resected articular surface 72 and wherein first and second lips 78a-b of the femoral component 70 are slid into respective grooves 79 a-b,the first and second lips 78 a-b being slid medial to lateral or lateralto medial.

FIG. 8 shows a tapered relationship between a femoral component 80 and aresected femur 90, which is another example of a mating relationshipbetween a femoral component 80 and a resected femur 90 that maintainsthe femoral component 80 on a tapered resected surface 88 of a resectedfemur 90.

FIG. 8 is a perspective view of a femoral component 80 having anexterior surface 82 and a tapered interior surface 84 that is beingmounted in the direction of arrow 89 onto a resected femur 90 having acomplimentary, tapered, mating resected surface 88, thereby securing thefemoral component 80 to the resected femur 90.

More specifically, component 80 comprises a body 85 having an interiorsurface 84 and an opposing articulating surface 82, each extendingbetween a lateral side 81 and a medial side 83. The interior surface 84has a substantially U-shaped transverse cross section that inwardlytapers. The taper may occur from the medial side to the lateral side orfrom the lateral side to the medial side.

In the embodiment of FIG. 8, U-shaped femoral component 80 is formedwherein the U-shaped cavity bounded by the femoral component constricts,i.e., decreases in size, medial to lateral. (In another embodiment, thefemoral component decreases in size lateral to medial and the interiorsurface 84 is configured with a mating surface). Femur 90 is cut in amating configuration such that the femoral component 80 wedges ontofemur 90 as the femoral component 80 is slid in the direction of arrow89 onto femur 90 lateral to medial, thereby retaining the femoralcomponent on femur 90.

As reflected in FIG. 8, a method for resurfacing a femur 90 comprises:(i) resecting an articulating surface at a distal end of a femur 90 soas to form a resected articular surface 88 having an anterior surface 92and a posterior surface 94 each extending between a lateral side 96 anda medial side 98, at least one of the anterior surface 92 and posteriorsurface 94 being sloped relative to the other such that the anteriorsurface 92 and posterior surface converge toward the lateral side 96 ormedial side 98; and (ii) sliding a femoral component 80 onto theresected articular surface 88, the femoral component being 80 slidlateral to medial as shown or medial to lateral.

FIG. 8 a is a cross sectional view of an alternative femoral component80 a, having an articulating surface 82 a and a non-chamfered, curvedinterior surface 84 a, shown as mounted onto a resected femur 86 a.Anterior and posterior lips 88 a-b mate with corresponding grooves 89a-b in femur 86 a. FIGS. 7 and 8A demonstrate that a femoral componenthaving inwardly projecting lips 88 a-b can have a variety of differentinterior surfaces. The interior surface 84 a of the femoral component ofFIG. 8A can also be tapered similarly to FIG. 7 so as to mate with acomplimentary tapered resected femur, as discussed with reference toFIG. 7.

As another feature of the present invention, FIGS. 9-14 depictconnectible two-piece end use femoral components 102, 131, 161, and 191used in knee arthroplasty wherein the two parts are readily,independently slid in from the medial or lateral side through anincision and then connected and mounted onto a femoral resection.Optionally, one part may be mounted on the femoral resection followed byanother part being connected thereto. An attachment member, such as abolt or screw can then be inserted through the femur until contactingthe femoral component. A coupling member, e.g., a bolt or a screwattaches one part of the femoral component to another. The procedure isminimally invasive and does not require as large an incision as onepiece components because one part of the femoral component may be placedthrough the incision, followed by the other part of the femoralcomponent.

FIG. 9 is a perspective view of a two-piece end use femoral component102 divided lateral to medial, while FIG. 10 is a perspective view ofthe femoral component 102 shown in an assembled state. Femoral component102 is configured for “end use” in that it is configured to bepermanently mounted onto a resected articular surface during aresurfacing procedure so as to articulate against a tibia and/orprosthetic tibial component and is designed for actual daily use by apatient who has experienced the procedure in order to replace at least aportion of a knee.

FIG. 9 thus depicts a femoral knee prosthesis system 100 for resurfacinga resected articular surface at the distal end of a femur, comprising:end use femoral component 102 having (A) an interior surface 105 adaptedto mate with the resected articular surface and (B) an opposingarticulating surface 107.

The end use femoral component further comprises (i) a first portion,i.e., patellar condyle 103, comprising a first section of thearticulating surface; (ii) a second portion, i.e., tibial condyle 104comprising a second section of the articulating surface, the secondportion 104 being selectively mateable with the first portion 103; and(iii) bolts 106, 108 configured to selectively connect the first portion103 to the second portion 104. Bolts 106, 108 are examples of means forselectively connecting the first portion to the second portion. Bolt 124secures the femoral component 102 to the femur using the same method aspreviously discussed with regard to FIGS. 3, 4, and 6. However, avariety of other methods may be employed to secure the femoral componentto the femur, such as the use of bone cement or pegs compressed into theresected femur. In one embodiment, at least a portion of patellarcondyle 103 corresponds to an anterior portion of the resected femurwhile at least a portion of tibial condyle 104 corresponds to aposterior portion of the resected femur.

As shown, bolts 106, 108 extend through respective apertures 110 a-b,112 a-b, 114 a-b, 116 a-b along orientation lines 118 a-b to connectportions 103, 104 such that the combined condyle portions 103, 104collectively form the femoral component 102 shown in FIG. 10.

U-shaped femoral component 102 is divided along a joint 119 so thatfemoral component 102 comprises an anterior section 115 and a posteriorsection 117. At least one and preferably first and second passagewaysdefined by apertures 110 a-b, 112 a-b, 114 a-b, and 116 a-b extendlaterally through both anterior section 115 and posterior section 117such that when sections 115 and 117 are aligned, threaded bolts 106, 108can be laterally threaded into the passageways so as to secure themating sections.

During a resurfacing procedure, the first and second portions 103, 104are readily, independently slid in from the medial or lateral sidethrough an incision and then connected and mounted onto a femoralresection. Optionally, one part 103 or 104 may be mounted on the femoralresection followed by the mating part being connected thereto andmounted on the femoral resection.

A method for resurfacing a femur employing femoral component 102 thuscomprises (i) resecting an articulating surface at a distal end of afemur so as to form a resected articular surface; (ii) positioning afirst portion 103 of an end use femoral component on or adjacent to theresected articular surface, the first portion 103 comprising a firstsection of an articulating surface of the end use femoral component 102;(iii) positioning a second portion 104 of the end use femoral component102 on or adjacent to the resected articular surface, the second portioncomprising a second section of the articulating surface of the end usefemoral component 102; (iv) securing the first portion 103 of the enduse femoral component 102 to the second portion of the end use femoralcomponent; and (v) attaching the end use femoral component 102 to theresected articular surface, e.g., through the use of bolt 124, a screw,pin or other means for attaching.

FIG. 11 is a perspective view of a system 130 comprising a substantiallysimilar femoral component 131 having meshing teeth 136, 138 and dividedlateral to medial. Component 131 comprises (i) a first portion, i.e.,patella condyle 132, comprising a first section of the articulatingsurface; (ii) a second portion, i.e., tibial condyle 134 comprising asecond section of the articulating surface, the second portion 134 beingselectively mateable with the first portion 132; and (iii) bolts 142,144 configured to selectively connect the first portion 132 to thesecond portion 134 by extending through respective apertures 146, 148and additional apertures not shown. Bolts 142, 144 are examples of meansfor selectively connecting the first portion to the second portion. Bolt150 is an example of means for securing the femoral component 131 to thefemur.

As opposed to the smooth joint 119 of FIG. 10, femoral component 131 canbe formed with a joint 140 having complementary mating teeth 136, 138.

In yet another embodiment, as discussed with respect to FIGS. 12 and 13,the first portion comprises a substantially U-shaped lateral condyle(162) and the second portion comprises a substantially U-shaped medialcondyle (164).

FIG. 12 is a perspective view of a femoral component 161 of system 160divided anterior to posterior and FIG. 13 is a perspective view of thefemoral component 161 shown in FIG. 12 in an assembled state.

Femoral component 161 comprises: (i) a lateral condyle 162 having asubstantially U-shaped configuration and having a lateral side 163 andan opposing medial side 166 each extending between an anterior end 165and an opposing posterior end 167; (ii) a medial condyle 164 having asubstantially U-shaped configuration and having a lateral side 168 andan opposing medial side 169 each extending between an anterior end 171and an opposing posterior end 173. The lateral side 168 of the medialcondyle 164 is configured to mate with the medial side 166 of thelateral condyle 162 such that a slot 179 is formed between the medialcondyle and the lateral condyle at the posterior ends thereof.

Bolts 170, 172 are examples of means for connecting the medial condyleto the lateral condyle when the medial condyle and lateral condyle aremated. Bolt 178 secures the femoral component 161 to the femur. However,a variety of other methods may be employed to secure the femoralcomponent to the femur, such as the use of bone cement or pegscompressed into the resected femur.

Femoral component 161 is centrally divided anterior to posterior along alinear joint 180 so that femoral component 161 comprises a medialsection and a lateral section. At least one and preferably first andsecond passageways defined by apertures 174 a-b and 176 a-b extendlaterally through both the medial section and the lateral section suchthat when the sections are aligned, bolts 170, 172 can be laterallythreaded into respective passageways so as to secure the sectionstogether.

FIG. 14 is a perspective view of a femoral component divided anterior toposterior and having meshing teeth. FIG. 14 shows a system 190comprising a substantially similar femoral component 191 having meshingteeth 202, 204 and divided anterior to posterior. Component 191comprises (i) a first portion, i.e., lateral condyle 192, comprising afirst section of the articulating surface; (ii) a second portion, i.e.,medial condyle 194 comprising a second section of the articulatingsurface, the second portion being selectively mateable with the firstportion; and (iii) bolts 196, 198 configured to selectively connect thefirst portion to the second portion. Bolts 196, 198 are examples ofmeans for selectively connecting the first portion to the secondportion. Bolt 206 or other method of attachment can be employed tosecure the femoral component 191 to the femur.

As depicted in FIG. 14, in contrast to having a linear joint, femoralcomponent 191 can be formed with a joint having complementary matingteeth formed on each of the sections.

FIGS. 15A-16B demonstrate assembled and exploded views of anothertwo-piece femoral component of the present invention employingprotrusions in order to link the pieces of the component. The two partsare readily, independently slid in from the medial or lateral sidethrough an incision and then connected and mounted onto a femoralresection. Optionally, one part may be mounted on the femoral resectionfollowed by another part being connected thereto and mounted on thefemoral resection.

FIG. 15 depicts a femoral knee prosthesis system 210 for resurfacing aresected articular surface at the distal end of a femur, comprising: (i)end use femoral component 211 having (i) an interior surface 215 adaptedto mate with the resected articular surface and (ii) an opposingarticulating surface 217.

The end use femoral component 211 comprises (i) a first portion, i.e.,patellar condyle 214, comprising a first section of the articulatingsurface; and (ii) a second portion, i.e., tibial condyle 212 comprisinga second section of the articulating surface, the second portion 212being selectively mateable with the first portion 214. Specifically,second portion 212 of femoral component 211 has an interior surface 261,an opposing articulating surface 263, and a peripheral edge 264extending between surfaces 261 and 263. Peripheral edge 264 includes anoutside edge 266 and a recessed substantially U-shaped mating surface266. Protrusions 224-230 project from mating surface 266 of secondportion 212 and are configured to be received within first portion 214,thereby mating the first and second portions. In the embodiment depictedprotrusions 224-230 have a substantially cylindrical configuration.Passages 242 and 242 a extend from outside edge 266 to mating surface266 on opposing sides of second portion 212. Pegs 220-222 project frominterior surface 261 and are additional examples of means for securingthe femoral component 211 to the femur.

First portion 214 of femoral component 211 also has an interior surface268, an opposing articulating surface 270, and a peripheral edge 272extending between surfaces 268 and 270. Peripheral edge 272 includes anoutside edge 273 and a mating surface 274. Mating surface 274 has anoutwardly projecting, substantially U-shaped configuration that issubstantially complementary to mating surface 266 of second portion 212.Four spaced apart apertures 232, 238, 239 (fourth aperture not shown)are formed on mating surface 274 and are configured to receivecorresponding protrusions 224-230. In the embodiment depicted, eachaperture comprises a substantially cylindrical blind socket bounded byan encircling sidewall. Threaded apertures 244 and 244 a are formed onopposing sides of mating surface 274 so that threaded apertures 244 and244 a are aligned with passages 242 and 242 a when first portion 214 iscoupled with second portion 212.

Femoral knee prosthesis system 210 further comprises bolts 240, 240 a orscrews that are configured to connect first portion 214 to secondportion 212 once the protrusions 224-230 are mounted in first portion214. In one embodiment, an incision is made in only one side of theknee. Thus, only one of bolts 240 or 240 a is employed to connect firstportion 214 to second portion 212.

As shown, protrusions 224-230 extend through respective apertures 232,238, 239 (fourth aperture not shown) and bolt 240 is extended throughpassage 242 and into bored aperture 244 such that the combined condyleportions 214, 212 collectively form the femoral component 211 shown inFIGS. 15B and 16B. The use of protrusions 224-230 and at least one bolt240 forms a strong connection between first and second portions 214,212. Bolt 240 a is extended through aperture 242 a and into boredaperture 244 a in portion 214.

As discussed above, the femoral components of the present invention areconveniently slid in from the medial or lateral side through anincision. In addition, the femoral components of the present inventionmay be conveniently slid (either as one piece or two-piece members)through and incision in between the medial and lateral sides. Thefemoral components are designed to articulate against the tibia and/or aprosthetic tibial component.

It is appreciated that the various configurations, structures, andmethods as discussed above can be mixed and matched to form yet otherunique configurations, structures, and methods.

Additional disclosure relating to apparatuses and methods of the presentinvention is available in a U.S. patent application Ser. No. 10/445,288,filed May 23, 2003 entitled “Modular Femoral Components for KneeArthroplasty” with Daniel F. Justin and E. Marlowe Goble as inventors,which application is incorporated herein in its entirety by reference.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed is:
 1. A femoral component of a knee prosthesis forresurfacing a resected articular surface at the distal end of a femur,the femoral component comprising: a main body having an interior surfaceand an opposing articulating surface each extending between a lateralside and a medial side, the interior surface having a substantiallyU-shaped transverse cross section; at least one lip projecting inwardlyfrom an end of the interior surface of the body; an elongated bolthaving a threaded end; and a pre-threaded bore formed on the interiorsurface of the femoral component for connecting the elongated bolt tothe femoral component when the femoral component is mated on theresected articular surface of the femur and when the elongated bolt ispassed through the femur, the pre-threaded bore being angled such thatwhen the femoral component is mated on the resected articular surface ofthe femur, the bolt can be passed through the medial side or the lateralside of the resected articular surface so as to threadedly engage withthe pre-threaded bore.
 2. A femoral component as recited in claim 1wherein the femoral component comprises a first lip projecting inwardlyfrom an anterior end of the interior surface of the body and a secondlip projecting inwardly from a posterior end of the interior surface ofthe body.
 3. A femoral component as recited in claim 1, furthercomprising: a second attachment member; and means formed on the interiorsurface of the femoral component for connecting the second attachmentmember to the femoral component when the femoral component is mated onthe resected articular surface of the femur and when the secondattachment member is passed through the femur.
 4. A femoral component asrecited in claim 1, wherein the femoral component has a non-chamfered,curved interior surface.
 5. A femoral component as recited in claim 1,wherein the femoral component has a chamfered, angular interior surface.6. A method comprising: resecting an articulating surface at a distalend of a femur so as to form a resected articular surface having ananterior surface and a posterior surface each extending between alateral side and a medial side, at least one of the anterior surface andposterior surface having a groove therein; sliding a femoral componentonto the resected articular surface, a lip of the femoral componentmating with the groove, the femoral component being slid along one of apath extending medial to lateral, and a path extending lateral tomedial; passing an elongated bolt through the femur; and connecting theelongated bolt to a pre-threaded bore formed on the interior surface ofthe femoral component so that the elongated bolt secures the femoralcomponent to the resected articular surface.
 7. A method as recited inclaim 6, wherein the step of resecting an articulating surface comprisesforming first and second opposing grooves in the resected articularsurface and wherein first and second lips of the femoral component areslid into respective grooves, the first and second lips being slid alongone of a path extending medial to lateral, and a path extending lateralto medial.
 8. A method as recited in claim 6, further comprising:passing a second attachment member through the femur; and connecting thesecond attachment member to the femoral component so that the secondattachment member secures the femoral component to the resectedarticular surface.
 9. A femoral component of a knee prosthesis forresurfacing a resected articular surface at the distal end of a femur,the femoral component comprising: a lateral condyle having asubstantially U-shaped configuration and having an interior surface andan opposing exterior surface each extending between an anterior end andan opposing posterior end; a medial condyle having a substantiallyU-shaped configuration and having an interior surface and an opposingexterior surface each extending between an anterior end and an opposingposterior end, the medial condyle being connected to the lateralcondyle; a first engagement lip projecting from the interior surface ofat least one of the lateral condyle and the medial condyle at theanterior end thereof; a second engagement lip projecting from theinterior surface of at least one of the lateral condyle and medialcondyle at the posterior end thereof; an elongated bolt having athreaded end; and a pre-threaded bore formed on the interior surface ofthe femoral component for connecting the elongated bolt to the femoralcomponent when the femoral component is mated on the resected articularsurface of the femur and when the elongated bolt is passed through thefemur, the pre-threaded bore being angled such that when the femoralcomponent is mated on the resected articular surface of the femur, thebolt can be passed through the medial side or the lateral side of theresected articular surface so as to threaded engage with thepre-threaded bore.
 10. A femoral component as recited in claim 9,wherein an elongated slot is formed between the lateral condyle and themedial condyle.
 11. A femoral component as recited in claim 9, furthercomprising: a first attachment member; and means formed on the interiorsurface of the femoral component for connecting the first attachmentmember to the femoral component when the femoral component is mated onthe resected articular surface of the femur and when the firstattachment member is passed through the femur.
 12. A femoral componentas recited in claim 9, wherein the femoral component has anon-chamfered, curved interior surface.
 13. A femoral component asrecited in claim 9, wherein the femoral component has chamfered, angularinterior surface.
 14. A femoral component as recited in claim 9, whereinthe first engagement lip projects from the interior surface of thelateral condyle and the medial condyle as a single lip.
 15. A methodcomprising: resecting an articulating surface at a distal end of a femurso as to form a resected articular surface having an anterior surfaceand a posterior surface each extending between a lateral side and amedial side, a first groove being formed along the anterior surface anda second groove being formed along the posterior surface; sliding afemoral component onto the resected articular surface, the femoralcomponent having an interior surface and an opposing articulatingsurface, the femoral component being slid along one of a path extendingmedial to lateral and a path extending lateral to medial, such that afirst lip projecting from the interior surface of the femoral componentis received within the first channel and a second lip projecting fromthe interior surface of the femoral component is received within thesecond channel; passing an elongated through the femur; and connectingthe elongated bolt to a pre-threaded bore formed on the interior surfaceof the femoral component so that the elongated bolt secures the femoralcomponent to the resected articular surface.